Last week I saw a beautiful crafted soarer at nearby RC flying field. My friend build a scaled up Thermic sailplane. It is and old FF design made in 1946 by famous Frank Zaic. Of course, model is R/C and covered by Oralight.

I decided to build for myself original version of Thermic 70. Wing span is 70".

Plans werew downloaded from Internet:

I cut many 3x3mm balsa strips, as these are basic structure of the fuselage.

I made two identical fuselage sides (ladder):

Next I glue some fuselage formers to spread sides to proper distance and to get shape:

Next I add some additional longerons:

And in very short time, fuselage is ready for final sanding:

Of course, I need to instal servo, battery and reciever tray, install elevator and rudder pushrods, install fin ribs and make a removable canopy hatch for RC equippment access.

I started a new project of making drawings&plans for a former Yugoslav School glider. It was designed pre ww2, but modified to version II. after the great war.

There are at least two different 3view drawings of Galeb sailplane, but I opted to use (and stik to) a 3 view drawing from a national soaring magazine Narodna Krila (wings of nation), where an complete article was published about that Sailplane in 1948. The article was written by designer itself.

Picture above: 3 view drawing of teh Galeb from 1948.

For designing this scale RC model I purchased two special programs :

- DevFus for designing of fuselages

and

-DevWing, for designing of wings (and tail surfaces also)

As Galeb was strongly influenced by Grunau Baby design, I will make internal structure of this glider (placing ribs and diagonals) similar to Grunau Baby. Galeb is slightly different than Grunau baby:

Photo above: Rib test contraption. Note bottles and bucket filled with water as a ballast. Of course I weighted the proper ammount.

I am happy with results, as rib survive ultimate load and permanent deformation after ultimate load was almost next to none.

I made pretty primitive contraption for the test.

I use wooden board and clam it vertical into a vice on the bench.

I install rib to that board using a piece of the hardwood. I use bolts trough holes made at end of the rib tubes.

I hang weight to ribs using strong string and bottles filled with apropriate ammount of water and a plastic bucket also filled with water.

To protect strings against sliding off the proper location I wrapped joints with adhesive tape. I also protect strings against rubbing onto the gussets edges by wrapping gusset edges with a cardboard. It not looks nice, but it served the mission.

At end of the rin I attach an arrow alike aluminum sheet and close to it a ruller, where I measure the deflections under the load.

I made a photos of rib deflection at 0, 1, 4 and 6G Load:

1G test: deflection at end of the rib 0 mm

4G test: deflection at end of the rib 5 mm

6G test: deflection at end of the rib 9 mm

Permanent deformation after 6G load: 1 mm

So much for now. It seems to me, that I will stay with this rib design.

I build another gimbal, again from 2 mm thick aircraft grade plywood. I reinforce the corners of elements for greater stiffnes, encase the electronic, battery and install DVD writer anti vibration inserts.

I already made some test flights yesterday evening, but I was not satisfied with electronic component.. wirinf between sensors and controll board became very stiff on cold air and starts to mess with stabilization. I need to replace these stiff wires with a softer ASAP!

I made 3 slots for the sensor plate, so I can instantly change the camera attitude. It can aim level to horizont, 25° and 59° bellow the horizont, without use of spare RC transmitter channel.

I made couple of flights with my CIRUS HS-62. For the first time I mount a camera into the rear cockpit, to make some inside videos. Unfortunately, homemade transparent canopy plastic with many tiny imperfections on the surface, prevented perfect visibility from that angle. Outside world is pretty distorted. Anyway, I will show you here a shot clip from one of my flights, where I do a looping and a roll.

Today I finally took some time to test HK Alti logger (actually it is Altitude permit logger) in role of ordinary alti logger.

And what a day! I manage to use thermals and soar my Marabu so high, that I starts to feel uncomfortable (bad visibility..moisted air) so I drop flaps and sprial nose down to "safer" height. Of course I was trying to thermal on that low height and was going up. As dinner was served on the table, and I was also impatient to see what will show the Alti logger on the computer, I landed.